G21.19 ICD-10-CM Code: Other drug induced secondary parkinsonism
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Extrapyramidal and movement disorders (G20-G26)
G21.19
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther drug induced secondary parkinsonism
Parkinson-like symptoms caused by medications other than neuroleptics, such as certain antiemetics, antidepressants, or other drugs.
Buddy Insight
Other drug induced secondary parkinsonism captures parkinsonian symptoms caused by medications other than neuroleptics, such as antiemetics (metoclopramide), calcium channel blockers, valproic acid, or lithium.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 78
RAF 0.606
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 78
RAF 0.0
RXHCC
MappedHCC 161
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
Official- Other medication-induced parkinsonism
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for G21.19 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for G21.19 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for G21.19 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G21.19 in this effective period.
Use Additional
Official- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
Code Also
OfficialICD-10-CM does not list Code Also instructions for G21.19 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is G21.19 an HCC code?
Yes. G21.19 maps to Parkinson's and Huntington's Diseases under the V24 model but is not retained in V28.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
Work G21.19 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for G21.19
For G21.19to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed G21.19 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
G21.19 is the ICD-10-CM diagnosis code for other drug induced secondary parkinsonism. Parkinson-like symptoms caused by medications other than neuroleptics, such as certain antiemetics, antidepressants, or other drugs. G21.19 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering extrapyramidal and movement disorders (g20-g26).
Under the older CMS-HCC V24 model, G21.19 maps to Parkinson's and Huntington's Diseases (HCC 78) with a community, non-dual, aged base RAF weight of 0.606. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Clearly identify the specific medication causing the secondary parkinsonism in the documentation. Because G21.19 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G21.19 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Clearly identify the specific medication causing the secondary parkinsonism in the documentation
- •Code the adverse effect of the causative drug using the appropriate T-code from the poisoning section
Clinical Significance
Other drug induced secondary parkinsonism captures parkinsonian symptoms caused by medications other than neuroleptics, such as antiemetics (metoclopramide), calcium channel blockers, valproic acid, or lithium. Identifying the drug cause is critical because symptoms may be reversible with medication discontinuation, unlike idiopathic Parkinson's disease.
Documentation Requirements
- ✓Specific non-neuroleptic medication identified as the cause
- ✓Temporal relationship between drug exposure and symptom development
- ✓Parkinsonian features documented on examination
- ✓Provider statement attributing symptoms to the medication
- ✓Adverse effect T-code coded for the specific medication
- ✓Plan for medication adjustment or discontinuation
Use Additional Code
Commonly Confused Codes
- •G21.11: Neuroleptic induced parkinsonism: specifically for antipsychotic medications
- •G20.A1-G20.C: Parkinson's disease: idiopathic, not drug-induced
- •G25.1: Drug-induced tremor: tremor alone without full parkinsonian syndrome
- •G21.2: Secondary parkinsonism due to other external agents: for non-drug causes like toxins